Whitening agents for organic materials



Ing

are highly substantive.

Patented Feb. 9, 1954 WHITENING AGENTSFOR ORGANIC MATERIALS Heinrich Gold, Opladen, and Siegfried Petersen, Leverkusen- Schlebusch, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application October 5, 1949, Serial No. 119,757

Claims priority, application Switzerland October 16, 1948 8 Claims. (Cl. 117-335) The present invention relates to new whitening agents for organic materials, and to a treatment processing of fibrous materials such as paper and textile materials, is usually called whitening or optical bleaching. For this purpose a number of chemically widely different compounds has already been proposed, compounds which show differences partly in their optical behavior, partly in other properties.

According to this invention, an exceptional whitening effect on organic materials is achieved by means of salts of sulfonic acids of such substantive compounds as contain several 1,2,3- triazole rings per molecule. These compounds are derived from diamines such as benzidine or diaminostilbene disulfonic acid. As an example of the new compounds may be mentioned 4,4- bis [5' sulfonaphtho 1,2':4,5 triazolyl (2) l-stilbene-2,2-disulfonic acid. The compounds derived from stilbene are distinguished by an exceptional strength. The compounds in question may be obtained in the usual manner by tetrazotizing the said amines, coupling the tetrazo compounds with amines which couple in a position adjacent to the amino group-for instance with 2-amino naphthalene or its sulfonic acids or their substitution products-and converting the ortho-amino azo compounds thus obtained in known manner into the triazoles.

The compounds according to the invention show weak greenish to violet fluorescence, and Their application takes place in the usual manner. of textile materials of cotton or regenerated cellulose, the compounds on account of their sub- 'stantive properties can simply by applied from a rinsing bath to the 'fibrousmaterial. Mostly In the treatment their application to textile materials will be effected. in the laundering or finishing process.

For such applications it is possible simply to add the whitening compounds to detergents to be sold, such as soap, soap substitutes, washing powders, and to finishing agents such as starch. For producing discharge effects of improved whiteness on colored textile materials, the compounds may either be already admixed to thedyestufi, or added to the dye bath, or finally mixed up with the discharge paste. It may be mentioned that the treatment with these compounds has also a favorable effect on dyed textile materials, since in many cases thus a clearer and more vivid shade is obtained. Our new agents can also be used for whitening wool; in this case a treatment in an acid bath at elevated temperature, say to (1., is expedient. In the paper industry the application takes place either in a dipping process in the case of finished papers, or by adding the compounds to the paper pulp during the manufacture. This application is not only of interest for ordinary papers, but also for special papers such as photographic papers. Since the compounds causing the whitening effect possess the property of absorbing ultraviolet light, paper or other wrapping materials treated therewith are suited for protecting materials sensitive to light, such as victuals and the like. Also with other organic materials to be bleached, such as plastics, artificial silk, light leathers, straw for hats, wood, soap and so on, the effective compounds are incorporated either in the final state or in any phase of their manufacture, just as it proves expedient or desirable. In all cases the whitish materials are considerably improved in their white appearance by this treatment. The whitening effect achieved with said compounds can considerably be increased in many cases by adding, if other conditions permit, salts e. g. Glaubers salt to the bath.

According to the field of application thecompounds are used in the form of their alkali, ammonium or alkaline earth salts; in case a soldbility of the salts in organic solvents is required, it is expedient to use the salts of amines.

Compared with the compounds already used or proposed for the optical bleaching, the compounds according to the invention show the advantage of highest substantivity. in addition to excellent fastness to washing, to boiling soda and to chlorine, and good fastness to light; The members The present invention is illustrated by the fol-: lowing examples; it is, however, not restricted thereto:

Example 1 The fabric to be whitened is -treated for minutes at a temperature of 40 C. with a liquor containing 0.05 to 0.06 gram of l,5l'-bis-[5'-sulfonaphtho 1',2:4,5 triazolyl (2)] stilbene 2,2-disulfonic acid per liter, rinsed and dried.

The material thus obtained shows a better whitetint than without this aftertreatment.

The compound applied is obtained by tetra,- zotizing 4,4-diaminostilbene-2,2f-disulfonic acid, coupling with 2 mols of 2-aminonaphthalene-5- sul'fonic acid and boiling the dyestuff obtained with ammoniacal copper sulfate solution. The same compound can be obtained by oxidizing the disazo-dyestuif from tetrazotized 4,4'-diaminostilbene-2,2'-disulfonic acid and 2 mols of 1- ami'nonaphthalene-5-sulfonic acid with ammoniacal copper sulfate. If instead of l-aminonaphthal'eneor 2-aminonaphthalene-5-sulfonic acid, 2 amino 5 methoxynapththalene '7- sulfonic acid or 2-amino-8-methoxy-naththalene-fi-sulfonic acid is used as coupling component, compounds are obtained the fluorescence of which appears less greenish.

Example 2 Yellowish white paper is treated with a solution containing 0.05 to 0.06 gram per liter of the compound mentioned in example one. After rinsing and drying the paper shows a distinct whitening effect.

The same effect can be achieved by the addition of 0.1 to 1 per cent of the same compound to the usual paper pulp.

Example 3 A slightly yellowish nettle cloth is treated at atemperature of 40 C. in a rinsing bath containing 0.018 gram of 4,4-bis-[5'sulfonaphtho- -1',2':.4,5 triazolyl (2)] stilbene 2,2disulfonic acid and 0.038 gram of [,stilbene-(Ml) lbis-[w-phenylurealelz-disulfonic acid, which urea can be obtained from 1 mol of 4,4' -diaminostilbene-2,2-disulfonic acid and 2 mols of phenylisocyanate. After rinsing and drying, the material shows a perfectly white, neutral, optical bleaching effect which remains unchanged also, after washing at the boil and the usual household bleaching.

Example 4 For a normal washing of white goods a washing agent is used which contains, besides the usual washing and cleansing agents and other admixtures, 2 to 3, grams of a. mixture of 4,47- bis [5. sulfonaphtho l',2':4,5 triazolyl- (2)[lstilb,ene-2,2'-disulfonic acid (18 parts) and Estilbene (4,4)] bis [w phenylureal 2,2- disulfonic acid (38 parts) per kilogram. After rinsing and drying the material shows a neutral optical bleaching eifect.

Example 5 Cotton is dyed in the usual way with 4 per cent of the dyestufi No. 670, Farbstofitabellen by Gustav Schultz, 7th edition. The dyeing thus obtained is discharged with a neutral Rongalite discharge paste, which contains 0.1 to 0.2 per cent of thecompound mentioned in. example one. cent of the compound mentioned in Example 1. The discharge appears whiter than without the addition of the whitening agent.

A similar white discharge eifect is obtained if in dyeing with the same dyestuif 0.05 to 0.01 per cent of the compound mentioned in Example 1 isadded to. the, dye. bath, and thereafter a neu- 1 tral Rongalite discharge is carried through.

Example 6 W001 is boiledfor 20 minutes in a bath containing 0.05. gram of MU-bis-[5'-sulfonaphtho- 1,2.':,4,5 triazolyl (2)] stilbene 2,2 disulfonic acid and 0.75 gram of sulfuric acid of 96 B. per liter. The material thus obtained shows a purer white than without this aftertreatment. A good eifect can already be obtained at a temperature of 40 to 50 C.

We claim:

1. A compound of the group consisting ofjacids of the general formula:

wherein X stands for a vinylene and m for a whole number from 0' to 1, and salts of such acids selected from the group consisting of the alkali metal, ammonium, alkaline earth and amine salts, said compounds being substantially colorless and possessing an excellent whitening efiect.

2. A compound of the general formula:

5 6. 4,4 bis [5' sulfonaphtho 1,2':4,5- triazo1y1-(2) ]-sti1bene-2,2'-disulfonic acid.

7. Sodium salts of 4,4-bis-[5'-sulfonaphtho 1',2' :4,5-triazo1y1- (2) -sti1bene-disulfonic acids.

8. The sodium salt of 4,4'-bis-[5-su1fonaph- 5 the 1',2':4,5 triazolyl (2)] sti1bene2,2-disulfonic acid.

HEINRICH GOLD. SIEGFRIED PETERSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,462,405 Keller Feb. 22, 1949 2,467,262 Knight Apr. 12, 1949 OTHER REFERENCES Ser. No. 381,856, Wendi; (A. P. 0.), published May 11, 1943. 

1. A COMPOUND OF THE GROUP CONSISTING OF ACIDS OF THE GENERAL FORMULA:
 3. WHITE ORGANIC MATERIALS HAVING INCORPORATED THEREIN AN EFFECTIVE AMOUNT OF A WHITENING AGENT AS DEFINE IN CLAIM
 1. 